Plasticization of polymerized styrene



a e t d a Great BritainFebruary19:1;13'13,t v if 3Claims. (c1. zen- 36aThe present application is a division of applipolystyrene to increasecation Serial No.i9 Q,032,;filed February l-1,-1938. does not increasethe power factor at 10 cycles 'The difierent synthetici resins formed bythe a second more than five times, 'Ifhe power polymerizati'onof"styrene" possess physical prcpfactor oipolys'tyreneitself 'is Q.'0Q02at 10 cycles ertiesg'parti'cularlyiias 'regards=fusibilitytand flex.'-per second v I ibil-i ty which t ary throughouta wide-range. z The 1 The'pl'a'sticizer may be incorporated with'the PATENT To CE I 1 itsplasticity" five rem polymers formed alf- 'highatemperaturestarereaderspolystyrene, either by adding to the monomerily fusible;but-arevery-brittlewhen--cold,wherelbefore' olymerization iby ot rolling withthe as polymers formedlat-room i-temperature are inpolymerized styrene,or by dissolvingalong with ia ea a t v ha; All types of polythepolymerized styrene in mere: of styrene'ha cellentinsulatingpropsubsequently evaporating thesolv nt.

erties. particularly? "a very high frequencies of Theionowingcomparativefigures of'the action mama solvent'and' ever necessary for manyelectrical purposes that have beenobtained'by' dissolving 30 grams Qf ththe=material be made appreciablymore flexible. polymerized"styrenesolduhder thet'rade name and less brit e, e. g g-in theproduction ot threads f of1 f Irolitul, in,1Q0' cclof benzene, shakingorfl 24 and; strandsfor insulating purposes in'boaitial hoursfandfiltering such a'solution' has a viseneral insular 'cosity 01330centistokes atZZOC; To 50-grams of j the filtrate'there was addedsufficient of the Many poposalsgha've previously been ma de' forsubstance tofbejtested to givef'thehesired per- :een sedtoplasticizeany"1: of this'i'solutio was 'run'over'the surfaceo fclear of 'a' wide -r of plastics' stitches-cellulose esters mercuryin ajcrystallizingfdish, the resulting jfilm and ether's al-ly j=*Du tohe-v'aried chemicalk'compositiorriof.t and p then remoyed and storedIo'ra furthenS the-p1as v that' in niany cases-ho"-=plasti=cizingveffect t'a kes last traces of solvent had beenremoved] The place, e., g. a plasticizer for one cOmpoundJisnot-J-filmstested were ,from l to i mils in thickness.

yfdifierent materials-asplasticentage, Slice. of benzene was addedand the'f er izee sty'r enew-m m'any case's whole, mixture shaken ctoefiectsolution. '3 cc.

riwp'olymeri'zedfvinylfiresins. gener-izs allowed tofremain onfthe""mercury'for48 hours 3 I necessarily a plasticizer for another'.'QStrips Qfcm's, long and'5' mm sqin breadth cut 'It 'has 'also" 'beeniio irrd that in some cases fromjthefilrns were tested by beingpassed-bethere -is an appreciable'lo'ss'ofthese plasticizers in tweezrt-woibrass rods each 0.2 5" 'in diameter and a comparatively short timewith acorresponding 0.005'1 apart mounted onfla plate, the film beingfalling ofldn the-plasticizmg 'eflfectr "The boiling clampedby jaws 0.5"below the rods, and mainpoint of a compo'und may be taken'asugivingtained undera tension of 200 grams. The jaws forpracticalpurposes"a rough criterion "as .tov the weretnenmoved to andfro through an angle of Vapour pressure, I 280 so as to bend the stripround the brass rods i e't =i v 1 et "attach reciprocation; The numberof bends f plastl ns- "po ymer zedstyrene consists-1n before the stripbreaks is a measure of the plasadding thereto a chemicallystableihomocyclic .40 m of thematerial f the strip. The

carbon compound having twoor=threefusedrings ber of bends forpolystyrene itself without the that as ,3: vv v flmgh( P t ,2400 thataddition of other'substances was 8. possesses 1 electrimmentrand 1Scapable Of As a guide to' the percentages of plasticizer swellingpolystyrene. YE S e compound is i that may be used-the followingexamples are meant a compound that does not readily alter its H chemicalcomposition on exposure to air. By a r compound that possesses a lowelectric moment Example I is meant a compound that either does not haveany polar groups or has polar groups arranged Phenflnthlene inpercentages symmetrically or has a single chloro, carboxylic t0gflpmystwene gave the number of bends shown ester, or carboxylic groupcontaining not more than 5 carbon atoms; By a compound capable ofswelling polystyrene is meant an aromat 0 compound not possessinghydroxide or keto groups n 233; and also either without side chains orhaving only side chains containing not more than 5 carbon atoms. a a rThe electric moment of the compound is sumciently low in accordance withthe invention it the addition of suflicient or the compound to so assesFilms containing 20% of phenanthrene show signs of crystals indicatingthat the limit of solubility had been reached.

Example II a isoamyl naphthalene added in different percentages up to20% increased the plasticity of polystyrene, but the power factor withan addition of 15% was 0.0008. at cycles per second and, therefore, wasapproaching the allowable limit. 1

Example III a-n-propylnaphthalene increases the plasticity ofpolystyrene in percentages up to but higher percentages do not cause anyfurther increase in plasticity. The power factor of the mixturecontaining 15% is 0.0006.

Example IV 5 inethylnaphthalene increases the plasticity 6 when added inamounts at leastup to For amounts greater than 10% however, the powerfactor'exceeds 0.001.

The plasticizers according to the invention may be usefully contrastedwith certain substances excluded from the invention.

Polychlorinated diphenyl's sold under the trade names .Aroclor andPermitol havebe'en used as plasticizers, but they are unsymmetricalcompounds and increase the power factor of polystyrene unduly. Thus 6%of these substances gave a testresult of'40 bends but the power factoris raised to 0.0015 at 10 cycles per second.

Dibutyl phthalate has frequently been suggested as a plasticizer, but itpossesses a high electric moment. 2.7% is sufiicient to give a testresult of 40 bends but the power factor is 0.0015 at 10 cycles persecond.

10% of 9-bromophenanthrene gives a test result of 33 bends only and thepower factor is raised to 00033 at 10 cycles persecond.

10% of methyl-p-naphthyl ketone gave a test result of 63 bends butraised the power factor to 0.0126 at 10 cycles per second.

Benzene, toluene, and xylene have been suggested for use asplasticizers, but owing to their low'boiling point, the plasticity israpidly lost with time. The same thing is true of di-phenyl andnaphthalene (which are also excellent plasticizers) as shown by thefollowing results:

Methyl abietate has also been claimed and while it is useful fortemporary purposes it is not of permanent value due to its oxidizing toa brittle resin by taking up atmospheric oxygen and thus losing its.plasticizing power.

On the, other hand the effect of time with cer tain plasticizersaccording to the invention is shown in the following:

Number of Plasticizer' Quantity i bends before fracture Per cent Weeks 4l 2 5 4 41 Phenanthrene l 89 4 88 15 8 88 12 88 5 l lsoamylnaphthaleneg; 15 3 126 The following table shows the properties of certainsubstances that may be used in accordance with the. invention asplasticizers:

Pclymerized styrene plasticized by the addition of any of the compoundsaccording to the invention is particularly well adapted for theconstruction of dielectric wave guides, for use as insulation in coaxialcables, and for use as a dielectric of condensers particularly thoseintended for circuits in which very high frequency currents flow.

What is claimed 1. A method of plasticlzing. polymerized styrene thatconsists inmixing therewith octahydrophenanthrene andoctahydroanthracene.

2. A method of plasticizing polymerized styrene that consists in mixingtherewith between 5% and 25% of a mixture. of octahydrophenanthrene andoctahydroanthracene.

8. A composition of matter comprising polymerized styrene admixed withbetween 5% and 25% of a mixture of octahydrophenanthrene andoctahydroanthracene.

ARTHUR JAMES WARNER. ARCHIBALD ALAN NEW.

